MANUFACTURING METHOD OF ZINC-PLATED OR ZINC-PLATED AND ANNEALED STEEL PLATE BY CONTROLLING OF DIRECT-FIRED FURNACE Russian patent published in 2011 - IPC C23C2/02 C23C2/06 

FIELD: metallurgy.

SUBSTANCE: method involves preparation of steel plate having the following composition, wt %: 0,01≤C≤0.22, 0.50≤Mn≤2.0, 0.2≤Si≤2.0, 0.005≤Al≤2.0, Mo≤1.0, Cr≤1.0, P≤0.02, Ti≤0.20, V≤0.40, Ni≤1.0, Nb≤0.20 and iron and inevitable impurities obtained during melting are the rest; oxidation of steel plate in direct-fired furnace the atmosphere of which contains air and fuel at the air-to-fuel ratio of 0.80 to 0.95 for formation of layer of iron oxide 0.05 to 0.2 mcm thick and internal Si and/or Mn and/or Al oxide; reduction of steel plate at reduction speed of 0.001 to 0.010 mcm/sec for building-up of internal oxide as to depth and achieving of complete reduction of iron oxide layer, zinc plating with hot dipping method of reduced steel plate so that steel plate with coating on the basis of zinc is formed and if necessary, performing the alloying operation of the above steel plate with coating on the basis of zinc so that zinc-plated and annealed steel plate is formed.

EFFECT: method allows obtaining zinc-plated steel plate with high mechanical properties, good wetting ability of the surface, good adhesion; thus, non-coated sections are absent and TRIP-effect is maintained.

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